Cosmic ray tests of large area Multigap Resistive Plate Chambers

We have built Multigap Resistive Plate Chambers (MRPC) with six 300 μ m gas gaps and an active area of 158 × 82 cm 2 . The signals are generated on 2.5 cm wide copper pickup strips; these are read out at each end thus allowing the position of the hit along the strip to be obtained from the time difference. Using three of these chambers we have set up a cosmic tracking system in a similar manner as planned for the Extreme Energy Events (EEE) project. The details of the set-up are presented in this paper. In addition we discuss the time and position resolution of these MRPCs measured using cosmic rays.